Question

The negative of $q\mspace{6mu} \vee \sim(p \land r)$ is

• A. $\sim q\mspace{6mu} \land \sim(p \land r)$
• B. $\sim q \land (p \land r)$
• C. $\sim q \vee (p \land r)$
• D. None of these

Answer 1

Answer: (B)

$\sim q \land (p \land r)$

Answer 2

$\sim(q\mspace{6mu} \vee \sim(p \land r)) = \mspace{6mu}\sim q \land (\sim(\sim(p \land r)) = \mspace{6mu}\sim q \land (p \land r)$.